Al-Farabi (d. 950AD) was perhaps the most original and influential of all Muslim philosophers in the Middle Ages. Great thinkers within the Islamic world from Ibn Bajjah to Ibn Rushd, as well as many outside it, such as Maimonides, St Thomas Aquinas and Spinoza refer to his works with the greatest of deference. Al-Farabi's main contribution is the co-systemization of various spiritual disciplines in Islamic non-traditional culture, using them in a courageous and sophisticated manner for promoting a universal world view. According to his view, different cultures and human groups show similar behaviour in similar circumstances, which is evident among other areas in their language, religion, politics and music. The present work compares the Arabic terminology of Al-Farabi with that of his predecessors, by using their own sets of definitions. An English translation is also provided in a separate volume. Wherever possible, Greek parallel terminology is provided, together with the Hebrew and Latin terminologies used in the medieval translations of Al-Farabi's works. The work's two volumes include detailed indices, a detailed bibliography of the philosopher, and an interpretative essay.